This invention relates generally to improved torque analyzing apparatus. More particularly, but not by way of limitation, this invention relates to improved torque analyzing apparatus having a torsion spring frictionally connected with a torque input shaft.
U.S. Pat. No. 3,007,336 issued Nov. 7, 1961 to F. W. Livermont, clearly describes the structure in operation of a similar torque analyzing apparatus. In the apparatus described in the patent, an elongated coil spring is utilized to permit the gradual increase in the torque as is applied to the torsion bar. While that apparatus functions satisfactorily, it has been found to require less space to utilize a spiral or torsion spring in lieu of the coil spring.
The use of the torsion spring has proved to be generally satisfactory, but difficulty has been encountered in connecting the torsion spring to the torque input shaft. In the past, a plurality of lugs have been formed on the exterior of the torque input shaft that project into holes formed in the innermost coil of the spring. In order to form the holes in the spring, it has been necessary to heat treat the spring thus destroying some of the spring characteristics. Attempts have been made to reheat the spring to restore its original characteristics without complete success. For the most part, the springs have deformed at the approximate location of the end of the heat treat so that the torque applied causes the holes in the spring to become disengaged from the lugs on the shaft or results in breakage of the spring in the end of the heat treat.
In the instances where the spring did not break, but simply became disengaged from the lugs, difficulty was encountered in maintaining the accuracy of the analyzer. On occasions, the lugs would re-enter the holes causing a lag in the operation of the analyzer, or in some instances, would not engage at all resulting in total inoperability of the analyzer.
Accordingly, an object of this invention is to provide an improved torque analyzer including means for effectively connecting the torsion spring with the torque input shaft to obviate the disadvantages mentioned hereinbefore.